Good tip Re: fishing tackle shirts for carrying phones. Yeah carrying phones in hot weather is a hassle - I cycle wearing Craghopper Solardry shirts when it's sunny, bloody everlasting polypropelene material, UV blocking, very breathable and practically instant drying. I've got four, one is 22 years old, much used, and looks almost the same as the day I bought it, slightly faded. Pockets aren't large enough for my new phones though, so when I don't want to lug around a rucksack, I use a proper nerdy phone/tablet holster. My cheapo doesn't look quite as nice as this, but you get the idea:
https://www.ebay.co.uk/itm/226428243061